Question

What aspect of chromosome behavior most clearly accounts for Mendel's law of independent assortment?

- crossing over between homologous chromosomes during prophase I of meiosis
- independent alignment of different homologous pairs on the metaphase I spindle
-movement of sister chromatids to opposite poles at anaphase II of meiosis
- replication of chromosomes prior to meiosis
- movement of homologous chromosomes to opposite poles at anaphase I of meiosis

Answer 1

Mendel's law of independent assortment is accounted for by the random alignment of homologous chromosome pairs on the metaphase I spindle, which leads to various combinations of paternal and maternal chromosomes in each gamete.

Step-by-step explanation:

The aspect of chromosome behavior that most clearly accounts for Mendel's law of independent assortment is the independent alignment of different homologous pairs on the metaphase I spindle during meiosis I. This occurs because the orientation of tetrads (or pairs of homologous chromosomes) on the metaphase plate during metaphase I is random, which results in each gamete potentially containing any combination of paternal and maternal chromosomes. Consequently, the genes residing on these chromosomes can assort independently into gametes, adhering to Mendel's law.

While crossing over also contributes to genetic variety by exchanging DNA segments between non-sister chromatids of homologous chromosomes, it is the random alignment during metaphase I that directly leads to independent assortment. Recombination, as a result of crossing over, serves to further ensure that even genes on the same chromosome can sometimes be inherited independently, especially if they are far apart.